Traditional methods of manufacturing a header assembly for Implantable Pulse Generators (IPG) used in Cardiac Rhythm Management and Neuro-stimulation devices involve fixing electrical contacts that interface with the stimulation lead on a tooling pin and elastomeric separation seals between the contacts by over-molding the assembly with a liquid plastic resin. The resin solidifies to encapsulate the contact and seal assembly holding the components in place thereby making up the header assembly. With this method. the liquid resin may leak into the electrical contacts and the seals. If the resin leaks into the electrical contacts and seals or the header molding process does not work well for any reason, the entire IPG must be rejected.